Diamond clarity

From ArticleWorld


Diamonds contain many inclusions and impurities when they are mined. These inclusions may not be seen with the naked eye, but under a microscope, inclusions such as tiny crystals, feathers and clouds may be seen. Inclusions, if large enough, may spoil the clarity of a diamond. Inclusions are the internal defects of a diamond, whereas the surface defects are called 'blemishes'. Clarity is one of the 4C’s (cut, carat, color, clarity) under which a perfect diamond is graded. Diamonds are carefully graded under 10x magnification microscopes.

Contents

Inclusions and blemishes

There are numerous types of inclusions and blemishes, as well as different degrees of each. They are as follows:

  • Inclusions: clouds; feathers, including crystals and minerals; knots; cavities; cleavages; bearding; and internal graining.
  • Blemishes: polish lines; grain boundaries; naturals; scratches; nicks; and pits.

Grading

Below are the possible grades of clarity that may be assigned to a diamond.

There are various standard agencies such as GIA, EGL, AGS, etc… that use specific lab tests to determine the clarity of diamonds for the world market. Diamonds are studied under a 10x magnification microscope, which is considered the standard scale. The following are the various grades given to a diamond before they saleable:

  • FL: means the diamond is absolutely flawless.
  • VVS1 and VVS2: mean very very slight inclusions that are invisible to the naked eye. VVS1 denotes greater clarity than VVS2.
  • VS1 and VS2: mean very slight inclusions that are invisible to the naked eye.
  • SI1 and SI2: mean slight inclusions exist which may or may not be visible to naked eye.
  • I1, I2 and I3: means imperfect diamonds, as the inclusions are clearly visible. For I3, the inclusions are large and most visible to the naked eye.

Rarity and value

The higher the grade of clarity, the rarer and more expensive the diamond. Diamonds with higher grades of clarity are always more expensive, yet they represent only 20% of all diamonds. The other 80% are put into industrial works. Out of the 20%, most of the gems have inclusions that are visible to the naked eye only through close inspection, and those which are not seen are termed as 'eye-clean' stones. The most in-demand diamonds are VS and SI grades followed by F, IF and VVS, but the I-graded stones are not prefered at all. The F and IF are the rarest of qualities and are termed 'museum quality' or 'investment grade'.

Clarity enhancement

Diamond clarity can be enhanced with laser drills and fracture fillers. Clarity of a diamond can be improved with the help of a laser. Using a laser drill, a hole is drilled into the colored inclusion of the diamond. Acid is then used to burn away the remaining color of the inclusion. In this case the diamond is graded only after the treatment, and a professional vendor must never forget to mention such a treatment has taken place to an inspector prior to grading.

Cracked diamonds can also be treated by filling a fracture. Diamonds having undergone this enhancement are called 'fracture filled diamonds'. However, fractured filling can be detected upon close inspection because the filling agent will flash pink or orange. Thus, vendors must inform inspectors if this treatment has been performed. However, GIA does not grade such stones because fillers are not as permanent as the diamonds themselves. Often excessive heat will cause damage to the filling.